Excretion, through milk, of ptaquiloside in bracken-fed cows. A quantitative assessment

Abstract

The content of ptaquiloside (ptaq), a major Pteridium aquilinum carcinogen found in milk from cows fed bracken in Venezuela, has been estimated quantitatively in ils passage through bovines into milk. Six cows were given 6 kg/animal/d of fresh bracken fronds whose ptaq content was determined. Ptaq first appeared in milk 38 h after initially feeding this plant to the cows and continued to be excreted at a relatively constant level, after an induction period, for 62-70 h after the bracken diet had ceased. The average value of total ptaq excreted ([ptaq]e) from milk amounted to 8.60 1.16 % of the total ptaq ingested ([ptaq]) during the entire feeding period.